In Direct Sequence Spread Spectrum (DSSS) systems, it is possible for a high-powered, narrowband signal to jam a DSSS receiver. Due to the nature of the demodulating process in a DSSS receiver, a strong signal going into a despreader results in a strong signal coming out of the despreader. A receiver uses the despreader output downstream for two primary purposes: 1) to demodulate transmitted data, and 2) to determine the signal strength of the DSSS signal. If a high-powered narrowband signal enters the despreader, the high amplitude output of the despreader can deceive the receiver into thinking it is still properly tracking the DSSS signal.
Prior art methods for detecting jamming includes frequency based analysis of a DSSS signal at the pre-detection stage, for example analyzing the frequency-domain representation of the received signal. This requires extensive use of the Fast Fourier Transform (FFT), which burdens the processor and memory of a receiver as the FFT output over multiple time intervals must be stored during the processing of information. A new method of jamming detection, which can be readily added to an existing receiver with no additional hardware requirement and impose a minimum burden on the processor and memory is desirable.
Accordingly, there is a significant need for an apparatus and method that overcomes the deficiencies of the prior art outlined above.